Nissan Repair: Fan Speed Switch, fuse switch, nissan frontier

Question
I have a 2000 Nissan Frontier P/U 4-cylinder 2-wheel drive.

Yesterday, when I started the truck, the fan would only work in the #4 position (High).  It does not matter if it is in A/C mode or just fan.

Fuse?  Switch?  Fan motor?

How hard is it to fix?  How much if I take to a shop?  Does it need to be done by Nissan?

Thanks for your help and information.

Answer
Mark,

There is a resistor block that the fan switch interfaces with and it is located under the dash on the passenger side.  Just go down to the parts store and ask for the resistor for the fan speed and then you will know what it looks like when you go to replace it.  It is an easy job of just plug and play with a couple of screws holding it on.